Re: [ovirt-users] Good practices

Hi Colin, Take a look on Devin's response. Also, read the doc he shared that gives some hints on how to deploy Gluster. It is more like that if you want high-performance you should have the bricks created as RAID (5 or 6) by the server's disk controller and them assemble a JBOD GlusterFS. The attached document is Gluster specific and not for oVirt. But at this point I think that having SSD will not be a plus as using the RAID controller Gluster will not be aware of the SSD. Regarding the OS, my idea is to have a RAID 1, made of 2 low cost HDDs, to install it. So far, based on the information received I should create a single RAID 5 or 6 on each server and then use this disk as a brick to create my Gluster cluster, made of 2 replicas + 1 arbiter. What is new for me is the detail that the arbiter does not need a lot of space as it only keeps meta data. Thanks for your response! Moacir ------------------------------ *From:* Colin Coe <colin.coe(a)gmail.com&gt; *Sent:* Monday, August 7, 2017 12:41 PM *To:* Moacir Ferreira *Cc:* users(a)ovirt.org *Subject:* Re: [ovirt-users] Good practices Hi I just thought that you'd do hardware RAID if you had the controller or JBOD if you didn't. In hindsight, a server with 40Gbps NICs is pretty likely to have a hardware RAID controller. I've never done JBOD with hardware RAID. I think having a single gluster brick on hardware JBOD would be riskier than multiple bricks, each on a single disk, but thats not based on anything other than my prejudices. I thought gluster tiering was for the most frequently accessed files, in which case all the VMs disks would end up in the hot tier. However, I have been wrong before... I just wanted to know where the OS was going as I didn't see it mentioned in the OP. Normally, I'd have the OS on a RAID1 but in your case thats a lot of wasted disk. Honestly, I think Yaniv's answer was far better than my own and made the important point about having an arbiter. Thanks On Mon, Aug 7, 2017 at 5:56 PM, Moacir Ferreira < moacirferreira(a)hotmail.com&gt; wrote: > Hi Colin, > > > I am in Portugal, so sorry for this late response. It is quite confusing > for me, please consider: > > > 1* - *What if the RAID is done by the server's disk controller, not by > software? > > 2 - For JBOD I am just using gdeploy to deploy it. However, I am not > using the oVirt node GUI to do this. > > > 3 - As the VM .qcow2 files are quite big, tiering would only help if > made by an intelligent system that uses SSD for chunks of data not for the > entire .qcow2 file. But I guess this is a problem everybody else has. So, > Do you know how tiering works in Gluster? > > > 4 - I am putting the OS on the first disk. However, would you do > differently? > > > Moacir > > ------------------------------ > *From:* Colin Coe <colin.coe(a)gmail.com&gt; > *Sent:* Monday, August 7, 2017 4:48 AM > *To:* Moacir Ferreira > *Cc:* users(a)ovirt.org > *Subject:* Re: [ovirt-users] Good practices > > 1) RAID5 may be a performance hit- > > 2) I'd be inclined to do this as JBOD by creating a distributed disperse > volume on each server. Something like > > echo gluster volume create dispersevol disperse-data 5 redundancy 2 \ > $(for SERVER in a b c; do for BRICK in $(seq 1 5); do echo -e > "server${SERVER}:/brick/brick-${SERVER}${BRICK}/brick \c"; done; done) > > 3) I think the above. > > 4) Gluster does support tiering, but IIRC you'd need the same number of > SSD as spindle drives. There may be another way to use the SSD as a fast > cache. > > Where are you putting the OS? > > Hope I understood the question... > > Thanks > > On Sun, Aug 6, 2017 at 10:49 PM, Moacir Ferreira < > moacirferreira(a)hotmail.com&gt; wrote: > >> I am willing to assemble a oVirt "pod", made of 3 servers, each with 2 >> CPU sockets of 12 cores, 256GB RAM, 7 HDD 10K, 1 SSD. The idea is to use >> GlusterFS to provide HA for the VMs. The 3 servers have a dual 40Gb NIC and >> a dual 10Gb NIC. So my intention is to create a loop like a server triangle >> using the 40Gb NICs for virtualization files (VMs .qcow2) access and to >> move VMs around the pod (east /west traffic) while using the 10Gb >> interfaces for giving services to the outside world (north/south traffic). >> >> >> This said, my first question is: How should I deploy GlusterFS in such >> oVirt scenario? My questions are: >> >> >> 1 - Should I create 3 RAID (i.e.: RAID 5), one on each oVirt node, and >> then create a GlusterFS using them? >> >> 2 - Instead, should I create a JBOD array made of all server's disks? >> >> 3 - What is the best Gluster configuration to provide for HA while not >> consuming too much disk space? >> >> 4 - Does a oVirt hypervisor pod like I am planning to build, and the >> virtualization environment, benefits from tiering when using a SSD disk? >> And yes, will Gluster do it by default or I have to configure it to do so? >> >> >> At the bottom line, what is the good practice for using GlusterFS in >> small pods for enterprises? >> >> >> You opinion/feedback will be really appreciated! >> >> Moacir >> >> _______________________________________________ >> Users mailing list >> Users(a)ovirt.org >> http://lists.ovirt.org/mailman/listinfo/users >> >> > _______________________________________________ Users mailing list Users(a)ovirt.org http://lists.ovirt.org/mailman/listinfo/users